A flat panel detector (to be referred to as an FPD hereinafter) is used to perform X-ray fluoroscopy/radiography of blood vessels and organs. A micro angio detector (to be referred to as an MA hereinafter) has been devised for the extraction of fine portions (200 μm or less) such as perforating branches and asymmetric stents. An X-ray diagnostic apparatus has presently been developed, which includes both an FPD and an MA and can switch and use the FPD and MA.
The X-ray diagnostic apparatus capable of switching the FPD and the MA normally uses the FPD. This apparatus uses the MA to check a fine portion which cannot be checked with the FPD. The MA is placed in front of the FPD. An X-ray generating system is commonly used both when the FPD is used and when the MA is used. When switching the FPD and the MA, the operator needs to perform cumbersome operation of retracting and placing the FPD and the MA. In order to equalize the X-ray dose at the time of the use of the MA to the X-ray dose at the time of the use of the FPD, it is necessary to increase the size of the effective X-ray focal spot at the time of the use of the MA to that at the time of the use of the FPD. Increasing the size of the effective focal spot leads to a deterioration in image quality. That is, the guarantee of an X-ray dose has a trade-off relationship with a reduction in the size of an effective focal spot.